Tube support designs such as those that comprise perforated support plates that may be configured to support and/or to hold all of the steam generator tubes configured for use in a straight or U-tube style SG, may not meet particular design objectives when applied to a SG with helical tubes. For straight and U-tube style SGs the tubes may be inserted through the holes in the support plates and the tube ends inserted directly into the tubesheet(s). For alternate tube designs such as helical tubes, the tubes may be screwed through the holes in such support plates, but the tube ends must be either subsequently bent or bent tube segments welded to the tube ends to facilitate fit-up of the tube ends to the tubesheets. The welds or bends may not meet particular design objectives, and require additional inspection after installation. These additional processes and inspections are time-consuming, expensive, and introduce possible material defects late in the assembly sequence.
Tube support systems which rigidly clamp or otherwise hold the tubes in place may induce stress as a result of thermal expansion. Systems which include a large number of parts to mount and/or hold the individual tubes would require a significant amount of time for installation, inspection, and/or disassembly, and may introduce the possibility of improper assembly. In addition to increasing the assembly time, a large number of parts may increase the likelihood that one or more parts, e.g. screws, clamps, etc., may work loose during operation. Other types of tube support systems which include mounting holes and fit-up shims require complex assembly and restrict movement of the tubes prior to complete installation of the steam generation system. Additionally, it may be difficult to thread the tubes into a support structure which includes mounting holes or other types of mounting structures with restrictive tolerances. The present application addresses these and other problems.